Edge trimmer grinder



Nav l, 1938. E. DUNFORD 2,134,751

` EDGE TRIMMER GRINDER Filed Sept. 9, 1937 i @mas/L @a/9M Patented Nov. 1, 1938 LUNITED STATES PATENT OFFICE dis Machine Company,

ration of Missouri St. Louis, Mo., a corpo- Application September 9, 1937, Serial No. 162,967

11 Claims.

This invention relates to the art of grinding :rotary cutters of which one example is the cutter `used for trimming `the edges of shoe soles and `having a series of deeply recessed and peculiarly K shaped teeth. It is to be understood that the use ofthe invention is not limited to cutters of this specic class but such a cutter and the grinding wheel .therefor and elements of the mounting `for the cutter are illustrated in the associated i drawing.

The .lmainobject of the invention is to facilitate the application of a cutter tooth to the grinding wheel and `a quick removal of the cutter from the grinding wheel and the ready rotation of the cut- :ter on its ,mounting to present another tooth to thewheel.

Another :object of the invention is to insure the accurate spacing of the ground surfaces of successive teeth irrespective of the skill of the operator `and irrespective of the number of times that the cutter has been ground or the extent to which the original cutting surfaces have been Worn-down.

`Another object of the invention is to readily accommodate diierent diameters of cutters and variations in the thickness and diameter of the grinding wheel.

These general objectives and other more de tailed objectives as will be apparent from this specication, are attained by the structure illustrated in the accompanying drawing, in which: Figure :1;is, in part, a front elevation 0I" the end portion `only oi a shoe trimmer with a cutter grinding vwheel andcutter mounting Xture applied thereto, the portion oi the fixture being sectioned to more clearly illustrate its construction; Figure 2 is an end elevation of the structure shown in Figure 1; and

.'Figure 3 is a top view of so much of `the struc- 40 ture `as .necessary to illustrate certain features described.

Figurel -is a similar view showingthe parts in another position.

The end oi the trimmer frame, indicated at i, journalsa Vrotating shaft 2, projecting beyond the frame and carrying a grinding wheel 3. 'I'he cutter to rbe `sharpened on the wheel kis indicated at 4 and isof `a :familiar contour, embodying a series of radial yteeth 5, with their cutting edges ii facing circumferentially of the wheel.

The iixture which mounts the cutter comprises a bracket 1, the base of which ts against the end of the trimmer frame i vand is secured in place by screws 9. vA stud I il has its left hand end threaded-into albossisi on bracket land the right (o1. slums) hand end of stud Ill forms a pivot I2 for a cutter support arm I3, which can'oscillate about the stud axis. A handle I9 Von arm I3 facilitates the pivotal movement of arm I3 about stud Ill.

A knurle'd sleeve I5 secured to stud Il) enables 35 the user to rotate the stud and thereby shift pivot I2 towards and away from the bracket base or transversely of the plane of the grinding wheel 3. Screw I ii, threaded through boss II may be tightened to engage stud I il and hold it against the movement just described.

A cap I4 attached to the end of pivot I2 retains support arm t3. A spring 26 compressed between a shoulder on stud I() and arm I3 thrusts the latter to the right. There is a slight clearance in- 15 dicated at C (Figure 1l) between arm I3 and the edge of sleeve I5, permitting a slight movement of arm i3 to the left for the purpose hereinafter mentioned.

`The upper end of arm I3 terminates in a verti- 20 cally disposed spindle I 1, journalling cutter 4, there being a flange `I8 at the base of the spindle for supporting `the cutter.

An upstanding nger 22 is pivoted on arm I3 and a coil spring 23 tends to move finger 22 to- 25 ward the common axis of spindle I1 and cutter 4. During Vsuch movement the upper end of nger 22 enters the space between two successive teeth (Figure 3). The right hand face of finger 22 is disposed at such an angle Ithat it substantially 30 coincides with the `engaged cutting face of the tooth 5u. The opposite face y oi 1inger22 is beveled or rounded so that as the nger moves inwardly toward the cutter axis it engages tooth ib and holds the cutter against play about its 35 spindle, irrespective of variations in the space between teeth 5a and 5h as may result from repeated grinding.

A lug 2t on nger 22 is positioned to strike a pin 2i on bracket 1 to arrest the movement of arm 40 i3 away from the grinding wheel (Figure 4), but after elements 23 and 2l are engaged, heavier pressure on handle I9 will stretch spring 23 and the arm may be moved farther away from the wheel, nger 22 remaining stationary, clearing 45 the cutter so that the latter may be rotated on spindle Il to present a new tooth to the finger and to the wheel. y Movement of the arm inwardly towards the grinding wheel is positively limited by the engagement of `a lug 24 with a stop screw 50 25 adjustably mounted in a lug 2'! on the lower portion of the bracket. (Figure 2).

With the parts in position as indicated in Figure 1, the tooth face opposing the grinding wheel willbe spaced slightlytherefrom but upon manual 55 movement of arm I3 to the left to the extent provided by clearance C, the tooth face will be brought against the wheel, as indicated in Figure 3. When the surface of the tooth has been ground to the extent permitted by the contact of finger 22 with the next tooth, pressure on arm I3 is released, the tooth and wheel separating under the thrust of spring 26. The operator then rotates arm I3 on pivot I2 until the parts are in the position shown in Figure 4, whereupon the cutter Wheel may be rotated one tooth and the positioning and grinding operation repeated.

The construction described results in the uniform application of successive cutterteeth to the grinding wheel, irrespective of the operators skill, for the reason that finger 22 and spring 23 hold the cutter against movement about the spindle axis, and stop elements 24 and 25 limit movement of the cutter inwardly toward the wheel. Assuming that the cutter teeth are evenly spaced in the original article, it will follow that the successive grindings will be equal on all teeth due to the positioning of the tooth being ground by the engagement of iinger 22 with the next tooth and, assuming that the operator will grind all of the teeth on the cutter and not remove the cutter with only a few of the teeth ground. Even in the event of such an improper grinding operation, if the cutter is again placed on the fixture and the grinding operation performed throughout a complete rotation of the cutter on spindle I1, the cutting surfaces will be evenly spaced from each other as in the original cutter. If the cutter is very dull and the first application of teeth to the wheel does not produce keen edges, the repeated application will result in further removal of metal from the tooth face and this cycle may be repeated.

When the grinding wheel wears down, set screw I6 may be loosened and stud l0 adjusted to the left to bring the cutter mounting block closer to the wheel grinding face. With such adjustment, finger 22 is also moved bodily and the cutting face of the tooth will be maintained parallel to the grinding face of the wheel.

Obviously, details of the structure may be changed substantially from those illustrated and described above without departing from the spirit of the invention and the exclusive use of such modications as come within the scope of the claims is contemplated.

I claim:

1. In combination, a grinding wheel, a support arm pivoted about an axis substantially parallel to and substantially spaced from the axis of said wheel, said arm having a cutter journalling spindle adjacent to said wheel with its axis extending transversely of said wheel axis, a nger pivoted on said arm about an axis extending transversely of the axis of said spindle, said iinger terminating adjacent to said spindle and having an element tapered to enter the recess between two cutter teeth so that its opposite sides engage a cutter tooth cutting face and an opposing face of an adjacent tooth, and a tension spring connecting said arm and iinger and thrusting said finger inwardly of said recess, to effect such engagement.

2. In combination, a grinding Wheel, a bracket, a support movable thereon substantially parallel to the plane of the grinding surface of said wheel and including a spindle for journalling a circular cutter so that it may rotate in a plane transversely of said iirst mentioned plane, a part movable on said support into position to engage a cutter tooth, a stop on said bracket engaging said part and limiting its movement with said support, said support being movable with said cutter after said stop and part engage to free said cutter from said part.

3. In a device of the class described, a grinding wheel, a xture for mounting a cutter to be applied to said wheel and comprising a fixed bracket, a stud mounted on'said bracket, and the axes of said stud and wheel being substantially parallel, means for securing said stud at various points transversely of the plane of said wheel, an arm having a cutter journalling spindle and oscillating on said stud to move said spindle towards and away from said wheel, and means for engaging the cutting face of a cutter to position the cutter and to hold the same positively against rotation on said spindle during the grinding operation.

4. A device as described in claim 3 in which the cutter holding means moves with the arm for a portion of the movement of the latter, the device including stops which then hold said means against movement with said arm so that said arm and a cutter thereon may clear said means and accommodate rotation of said cutter to present another tooth to the grinding wheel.

5. In a grinding fixture of the class described, an oscillating support for a circular cutter, spaced devices for limiting the oscillating movement of said support, a member movable to different positions on said support to engage the cutter or to release the same, said member moving with said support to hold said cutter to properly present a tooth to the grinding wheel and said member cooperating with one of said devices to be held against movement with said support to free the cutter from said member and permit the rotation of the cutter on said support to present another tooth to said wheel.

6. In combination, a grinding wheel, a station'- ary pivot, a support arm mounted on said pivot, whereby said arm may swing towards and away from the axis of said wheel, there being a cutter journaling spindle on said arm with its axis extending transversely of said wheel axis whereby a cutter rotated thereon may present successive teeth to the grinding face of said wheel, means on said arm for holding a cutter against rotation on said spindle, said arm having sliding movement on said pivot to bring a tooth face against said wheel.

7. A device as described in claim 6 which also includes means yieldingly thrusting the arm along its pivot away from the grinding face of the wheel.

8. In combination, a grinding wheel, a stationary pivot, a support arm mounted on said pivot whereby said arm may swing towards and away from the axis of said wheel, there being a cutter journaling spindle on said arm with its axis extending transversely of said wheel axis whereby a cutter rotated thereon may present successive teeth to the grinding face of said wheel, means on said arm for engaging a cutter tooth other than the tooth being ground to hold the cutter against rotation on said spindle, said arm having sliding movement on said pivot to bring a tooth face against said wheel.

9. A device as described in claim 8 which also includes means yieldingly thrusting the arm along its pivot away from the grinding face of the wheel.

l0. In a device of the class described, a grinding wheel, a stud with its axis disposed substantially parallel to the axis of said grinding wheel, a portion of said stud comprising a pivot, an arm mounted on said pivot and adapted to support a cutter in position to have its teeth presented to said wheel, said arm being rotatable on said pivotments and means cooperating to determine the to move a cutter towards and away from the periphery of said wheel and said arm being slidable on said pivot to move the face of a cutter tooth towards and away from the grinding face of said wheel, there being opposing elements on said arm and stud limiting the sliding movement of said arm, there being means on said arm for holding said cutter in position thereon, said eleeXtent of grinding which can be eiected on a cutter tooth at a single presentation of a tooth to said grinding wheel.

ll. A device as described in claim 10 which also includes means yieldingly thrusting the cutter supporting arm away from the grinding wheel.

ERNEST DUNFORD. 

